3½" & 5¼" Disk Drives
3½" & 5¼" Floppy Disc Drives are not the Amstrad standard yet the media and drives were far cheaper so they were common especially as a 2nd drive.
Especially the 3½" is used because the discs were available in the shops and you can also easily find such drives in any garbage if you properly scavenge old rusty computers.
Both 3½" & 5¼" drives were often double sided and supported double density and high density.
Nowadays it's often easier to use a disc drive emulator #or one of the devices that can run games from SD cards.
Contents
Usage of Media
To make full use of the capacity of the media you need to use another DOS on your CPC which can support more tracks and two sides. Then you can use around 720KB per disc.
Without another DOS you can still use some of the capacity:
- 3½" discs can't be turned like 3" discs therefore with AMSDOS you can use a manual side switch to choose the sides giving 2 x 178KB per side. Without the side switch it's just 178KB.
- 5¼" discs can be turned and you can write both sides if you cut a write protect hole on the other side.
Common PC Formats
3½":
- DD = 720KB
- HD : 1,44 MB
5¼":
- DD = 360KB
- HD = 1.2MB
Beware : HD
Nowaday the most common 3"1/2 disk is HD. These can be found as used or new old stock on auction sites.
But our beloved CPC can't understand easily the concept of High Density Disk with 1,44MB available... so you have to cheat to use the media: just put some opaque duct-tape (scotch-tape, whatever...) on the HD Hole.
Tada the drive will think DD media is used and now it's usable.
PC users used to do the opposite : file a HD hole on DD disk...this worked well sometimes.
You can also modify your HD drive to behave as a DD one (but this would be permanent of course).. Check for appropriate jumpers on your drive!
A clever choice
A great advantage at the time (in the 80's) was to get access to CP/M sofware library, as most of those were on such Floppy Disks.
Also, those Floppy Disks were far cheaper than the exotic 3", but... few CPC users actually own such drives.
Mostly professionnal users...The common snotling Gamer couldn't even dream of this (nor even knew it possible)... until nowadays.
As the magnetic disk is bigger...well the format is bigger too. It is common to get 720KB disk (using the 2 sides, so 80 tracks)
Software's issues
Many Modern CPC users replace their old 3" with an external 3"1/2, often adding a Disk drive A-B / B-A switcher (allowing the use of an external disk Drive as if it were the internal one = Drive A) and/or a side switcher to allow the use of a 3"1/2 disk like a 3" disk... switching manually the sides as needed by good old 3" disk drives (yet a decent software can do it).
The side switcher and A-B drive's switchers are needed only if you use old software (using AMSDOS), as most of them couldn't really figure they were loaded from B drives, or had no such feature as double sided drives.
They were designed for good old 3" drive so the 720KB DD external 3"1/2 is not implemented.
But modern software designers can allow this fairly easily.
Orion Prime uses the Double side feature, enabling a simple 720KB disk with no manual side switches.
Rick Dangerous 128+ (1.1 add-on) seems to allow the game to be loaded from the B drive.
It is up to the CPC-scene to design their software to include those options, allowing more un-modded drives to be simply used as external B drives with no need to add extra buttons and cable assemblies on the Amstrad.
As modifying all the software library of the good old times seems impractical, yet modern era software have to use this.
Software released on 3.5" disk
- Orion Prime - This pure awsomeness even uses a full DD disk's 80 tracks with more than 700KB of Data, but you have to have a proper DD disk drive, as some older models may lack this feature...
Software released on 5.25" disk
- Data Media released several software titles for use with their Data Media Disc System
Non 3" CPC disk drives
- Data Media Disc System
- Jasmin AM5D 5 "1/4 floppy drive
- KDS 5¼" Disc Drive (KDS Electronics)
- Vortex Disc Drives (Vortex)
- any scavenged rusty junk may be good enough nowaday, if you have a 664 or 6128...
Guides
Guide on how to connect a 3.5
Guide on how to connect a 3.5" drive to a CPC6128/664 with photos
Amstrad Computer User magazine published a two-page guide on how to connect a 5.25" drive to a CPC 464:
